1. Field of the Invention
The present invention relates generally to electrical contacts and to a method and apparatus of making the same. More particularly the invention concerns a precision apparatus for making electrical contacts of the character having specially configured spaced apart tongues adapted to mate with plug connectors of standard design.
2. Description of the Prior Art
Various methods have been suggested in the past for the high volume manufacture of electrical contact members. In one common prior art method the contact members are stamped or lanced from a suitable piece of sheet material and the contact tongues formed or coined as necessary. Another method of making electrical contacts by one or more bending operations is described in British Patent No. 836,397. Still another method, wherein the electrical contacts are made by splitting a bar of electrically conductive metal longitudinally over a portion of its length to form two contact tongues, is described in U.S. Pat. No. 4,040,177 issued to Beeler et al.
In one form of the aforementioned Beeler et al patent, a portion of the bar to be split is enclosed between two tools. The tools are then moved, sliding along each other perpendicular to the longitudinal dimension of the bar in mutually opposed directions, over a distance with is sufficient to produce the desired splitting. In another method of splitting, the bar to be split is retained over a part of its length such that one end is free, after which a wedge is longitudinally driven into the bar through this end.
Experience has shown that in order to repeatedly produce precision electrical contacts by a splitting or skieving method, it is absolutely essential that the portions of the material immediately adjacent the boundaries of the split or slice be rigidly and positively constrained. Only in this way can a predictable controlled shear split of the material be achieved. The recognition of this problem and its novel solution is at the very heart of the present invention. As will be better appreciated from the discussion which follows, the unique apparatus of the present invention, which closely constrains the starting material along the boundaries of the skieve or split, overcomes the basic deficiencies of the prior art splitting methods, including the Beeler et al method, and for the first time permits the low cost, large volume manufacture of very high quality precision electrical contacts.